1. Field of the Invention
The present invention relates to an automatic dispensing system for preparing various kinds of solvent mixture and more particularly to a system for automatically preparing various kinds of dyeing solvent by mixing mother dyeing solutions.
While the preferred embodiment of the present invention is directed to a system for automatic preparation of dyeing solvent, it should be understood that the present invention is applicable to any type of system that is intended for mixing stocks into the desired solvent mixture.
2. Prior Art
Systems have been developed which use a computer for automatically controlling the preparation of a solvent mixture in various fields such as chemical analysis and chemical testing, as well as color matching of dyeing solutions, paints and inks.
Japanese Patent Public Disclosure No. 122068/1980 shows an automatic dispensing system for preparing a dyeing solution comprising tanks of various stock solutions, each of which is connected to a receptacle through a liquid channel such as a pipe, with a dispenser being provided part way along each liquid channel. Commands from the computer control the operation of each dispenser so that the desired flow of each stock solution is supplied to the receptacle.
Japanese Patent Public Disclosure No. 159342/1981 shows an automatic dispensing system for preparing a dyeing solution, wherein the solvent coming from the pipe and received by a receptacle is detected by a sensor, and a valve on the effluent pipe connected to the stock solution is controlled by a computer. However, these two systems have the following defects:
(1) The system configuration is complex since different stock solutions must be connected to the receiving vessel through respective pipes, and dispensers or valves capable of flow control must be provided for each pipe of the feed. The greater the number of types of stock solution needed, the more complex the system configuration becomes; PA1 (2) The feed material adheres to the inner wall of the pipe and may cause clogging. Once such clogging occurs, it is very difficult to remove by washing; and PA1 (3) A viscous stock solution involves difficulty in terms of its conveyance through thin pipes and exact metering.
Japanese Patent Public Disclosure No. 66171/1982 shows an automatic dispensing apparatus for preparing a dyeing solution comprising a rotary table and a plurality of dispensers fixedly positioned around the table. The table consists of two stages that rotate relative to each other and each of which has a stock container and a receptacle. The operation of the rotary table in association with the dispensers is controlled by a computer. This system is defective in that the number of stock containers and receptacles that can be mounted on the rotary table is limited because of the necessity for using a relatively low-power motor.
Japanese Patent Public Disclosure No. 122068/1980 also shows an automatic dispensing system which has a movable dispenser, rather than piping, between a plurality of stock tanks and a receiving tank. In operation, the dispenser is moved to a desired stock tank from which a predetermined amount of stock solution is drawn; the dispenser is then moved to the receiving tank into which the stock solution is dispensed. This type of apparatus is free from the problems associated with the use of piping, but it still has the following defects. First, the pipette must be cleaned before a different type of stock solution can be sampled, and this causes an unavoidable interruption in the sample preparing operation. As a further disadvantage, the dispenser uses a single pipette for drawing and dispensing different types of stock solution, so if the amount of the stock solution to be drawn is greater that the capacity of the pipette, several drawings of the stock solution are necessary. If, on the other hand, a predetermined amount of the stock solution to be drawn is considerably smaller than the capacity of the pipette, a precise metering will become difficult.
All of the conventional systems shown above have one common problem; that is, they are not adapted to completely automated dispensing operations because when the initial supply of stock solution is consumed by a dispensing operation, subsequent dispensing operations are impossible without replenishing the stock solution manually.
The present invention has been accomplished to eliminate these problems of the conventional systems.